Posts Locator Order-by Filter tutorial ( part 7 )

gistfile1.txt

function gmw_orderby_filter( $clauses, $gmw ) {
	global $wpdb;

	//check if order-by value was submitted. If it was we will use its value otherwise we set the default value to 'distance'
	$orderby_value = ( isset( $_GET['gmw_orderby'] ) && !empty( $_GET['gmw_orderby'] ) ) ? $_GET['gmw_orderby'] : 'distance';
	 
	//check the value of the order-by and modify the clause based on that
	//when order-by distance
	if ( $orderby_value == 'distance' ) {
		/*
		 * when we do order-by distance we must check an address was entered.
		 * we cannot order results by distance when ther is no address to calculate distance to
		 * and so we will rsults with an error.
		 * So we check for the address and if address found we will order results by distance.
		 * Otherwise, we can order results by a different value. In this example i use post_title
		 */
		if ( isset( $gmw['org_address'] ) && !empty( $gmw['org_address'] ) ) {
			//order by distance when address entered
			$clauses['orderby'] = 'distance';
		} else {
			//if no address order by post title
			$clauses['orderby'] = $wpdb->prefix.'posts.post_title';
		}
	} elseif ( $orderby_value == 'post_title' ) {
		$clauses['orderby'] = $wpdb->prefix.'posts.post_title';
	} elseif ( $orderby_value == 'post_date' ) {
		$clauses['orderby'] = $wpdb->prefix.'posts.post_date';
	} elseif ( $orderby_value == 'post_id' ) {
		$clauses['orderby'] = $wpdb->prefix.'posts.ID';
	} elseif ( $orderby_value == 'random' ) {
		$clauses['orderby'] = 'RAND()';
	}
        
        //return modified clauses
	return $clauses;
}
add_filter( 'gmw_pt_location_query_clauses', 'gmw_orderby_filter', 20, 2 );